Synthesis and some reactions of hexahydro-1,2,4-triazine-3,6-dione

The synthesis of hexahydro-1,2,4-triazine-3,6-dione by hydrogenolysis of 1,2-dibenzylhexahydro-1,2,4-triazine-3,6-dione is reported. Ring contraction of the former dione to 3-amino-2,4-imidazolidinedione is discussed. The preparation of the 1- and 2-benzyl derivatives of hexahydro-1,2,4-triazine-3,6-dione and their conversion to the unsubstituted product are also described.